The present invention relates to method and apparatus for assembling a magnetic tape cartridge and, in particular, to method and apparatus for assembling a magnetic tape cartridge of a type that a single reel with magnetic tape wound therearound is rotatably stored in a cartridge case.
Conventionally, as a magnetic tape cartridge which is employed as a recording medium for use in an external storage such as a computer or the like, there is known a magnetic tape cartridge of a type that magnetic tape is wound around a single reel. This type of magnetic tape cartridge is used for data retention in a computer or the like and, since important information is stored in-the magnetic tape cartridge, the magnetic tape cartridge is .structured in such a manner that occurrence of a trouble such as jammed tape or the like can be prevented and also the unexpected draw-out of the magnetic tape can be prevented.
Here, FIG. 13 is an exploded perspective view of the above-mentioned magnetic tape cartridge which is known as DLT (digital linear tape).
Referring to the magnetic tape cartridge 1 shown in FIG. 13, magnetic tape 20 is wound around a single reel 3 consisting or a combination of an upper reel 4 and a lower reel 5 welded together by ultrasonic waves, and the single reel 3 is rotatably stored in a cartridge case 2 which comprises an upper case 2a and a lower case 2b fastened together by screws 19 or the like.
The upper reel 4 comprises a cylindrical-shaped bottomed reel hub 42 on the outer periphery of which the magnetic tape 20 can be wound, and a flange portion 93 which is projected in the radial direction of the upper reel from the outer periphery of the upper end of the reel hub 42; and, the reel hub 42 and flange portion 43 are formed of synthetic resin as a united body. And, on the outer surface of the bottom portion of the reel hub 42, there are cut and formed securing teeth serving as engaging mechanism which are used to drive and rotate the upper reel 4; and, on the outer peripheral edge of the flange portion 43, there are cut and formed restricting gears 43a with which a pair of front and rear reel brakes 50 and 51 can be meshingly engaged when restricting the rotation of the upper reel 4 while not in use. By the way, as shown in FIG. 13, the bottomed recessed portion of the reel hub 42 is opened upward.
On the other hand, the lower reel 5 is formed as a disk including in the central portion thereof an opening through which the outer surface of the bottom portion of the reel hub 42 can be inserted, and the lower reel 5 can be welded by ultrasonic waves to the upper reel 4 to thereby provide a united body.
Referring further to the reel 3 comprising the upper and lower reels 4 and 5 which are welded together in the above-mentioned manner, when assembling the reel 3 into the cartridge case 2, a bearing 6 is pressure inserted into and fixed to the bottomed recesses portion of the reel hub 42 and a spring plug 7 is further pressure inserted into and fixed to a hole formed in the central portion of the bearing 6. And, a reel spring 8, which consists of a compression coil spring mounted on the spring plug 7, energizes the reel 3 downward and holds the reel 3 in a freely rotatably manner.
Also, in order to prevent the reel 3 from rotating unexpectedly when the magnetic tape cartridge 1 is not in use, the reel 3 is secured by the front and rear reel brakes 50 and 51 which can be engaged with the restricting gears 43a by energizing forces given by brake springs 12 and 13 respectively consisting of torsion coil springs. Further, in the magnetic tape cartridge 1, in a state where the magnetic tape 20 is completely wound around the reel 3 when the magnetic tape cartridge 1 is not in use, a leader tape (mechanism by which a recording and reproducing apparatus using the magnetic tape cartridge 1 introduces the magnetic tape 20 to a given tape travel passage provided within the recording and reproducing apparatus) 21 is secured to the leading end portion of a hook 18 which is incorporated into the portion of the magnetic tape cartridge 1 that is located near to the side surface thereof.
In the respective given side walls of the upper and lower cases 2a and 2b which cooperate together in forming the cartridge case 2, there are formed cutaway portions 24a and 24b that cooperate together in forming a magnetic tape pull-out opening 24 of the cartridge case 2 through which the magnetic tape 20 can be pulled out. And, in the magnetic tape pull-out opening 24, there is mounted a lid 30 which can be opened and closed in the direction of the plane of the magnetic tape cartridge 1; in more particular, the lid 30 is journaled on a lid support shaft 14 in a freely openable and closable manner and can be energized in its closing direction by a lid spring 15 formed of a torsion coil spring; and, further, the, lid 30 is secured by a lid lock 40 properly energized by a lid spring 16 in order to be able to prevent the lid 30 from rotating when the magnetic tape cartridge 1 is not in use. Also, at the position on the opposite side of the cartridge case 2 that is opposed to the lid 30, there is incorporated a light protect piece 17.
And, if the above-mentioned magnetic tape cartridge 1 is set in its corresponding recording and reproducing apparatus such as an external storage or the like, then rotation drive mechanism provided on the apparatus side is engaged with the securing teeth of the reel 3 exposed to an opening 2c formed in the central portion of the lower case 2b against the energizing force of the reel spring 8 and, at the same time, the lid 30 is opened by a tape null-out mechanism provided on the apparatus side and the leader tape 21 is thus pulled in to a given position in the tape travel passage, thereby enabling data to be written into and read from the magnetic tape 20.
By the way, when assembling the above-mentioned magnetic tape cartridge 1 comprising a large number of parts, in order to be able to assemble as many parts as possible in a unit time as well as reduce the cost thereof and avoid as much defective assembling as possible, it is necessary to use an automatic assembling apparatus.
As such automatic assembling apparatus, there is available an assembling line in which a plurality of assembling stations each including an assembling robot for receiving works sequentially fed by delivery mechanism such as a belt conveyor or the like and also for assembling various parts to the works are arranged in a straight line manner. That is, the present assembling line is a multipurpose automatic assembling apparatus in which, by changing properly jigs to be mounted on the manipulator leading end portions of the assembling robots in the respective assembling stations, parts different in shapes can be assembled sequentially.
When assembling the magnetic tape cartridge 1 using the above-mentioned automatic assembling apparatus, for example, at first, the upper case 2a to be handled as the work is set on a pallet placed on a belt conveyor while it is reversed or turned upside down; various Darts such the reel spring 8, brake springs 12 and 13, front and rear reel brakes 50 and 51, lid spring 15, lid 30, hook 18, light protect piece 17 and the like are previously assembled to the thus reversed upper case 2a at the respective assembling stations; next, the reel 3 is assembled onto the upper case 2a; and, after then, the lower case 2b is assembled onto the upper case 2a. 
However, the magnetic tape cartridge 1 comprises a large number of component parts which are previously assembled while they are elastically energized by the spring members such as the reel spring 8, brake springs 12 and 13, lid spring 15 and the like; and, therefore, when feeding the upper case 2a sequentially, the respective component parts are easy to drop off or fall down. That is, in the magnetic tape cartridge 1, there arises a problem that it is difficult to deliver the work using the delivery mechanism such as a belt conveyor and the like.
Also, in the magnetic tape cartridge 1, when assembling the reel 3 into the upper case 2a, the front and rear reel brakes 50 and 51 must be held in such a manner that the respective locking gear portions of the front and rear reel brakes 50 and 51 can be evacuated from the installation area of the reel 3, or the reel 3 must be held on the upper case 2a side against the energizing force of the reel spring 8 until the lower case 2b is assembled onto the upper case 2a. Due to this, when assembling the above-mentioned component parts in the assembling line in which the plurality of assembling stations are arranged in the above-mentioned straight line manner, there must be provided in the respective assembling stations hold mechanism which are capable of holding the front and rear reel brakes 50, 51 and reel 3 in the above-mentioned manner, which results in the complicated structures of the assembling stations.
Further, since a severe assembling accuracy is required of the magnetic tape cartridge 1, the behavior of the work to be delivered on the belt conveyor must be controlled accurately. This mechanism that the above-mentioned conventional automatic assembling apparatus is not able to provide such magnetic tape cartridge as can meet the severe assembling accuracy but the yield of the magnetic tape cartridge in the assembling process is lowered.
The present invention aims at eliminating the above-mentioned drawbacks found in the conventional automatic assembling apparatus. Accordingly, it is an object of the invention to provide improved method and apparatus for assembling a magnetic tape cartridge, In which a magnetic tape cartridge with an excellent assembling accuracy can be obtained with high productivity.
The above-mentioned object can be attained by, according to one aspect of the invention, a method for assembling a magnetic tape cartridge, the magnetic tape cartridge comprising: a reel including rotation-driving engaging mechanism for driving or rotating magnetic tape and, a restricting gear for restricting the rotation of the reel, the rotation-driving engaging mechanism being formed on the outer surface of the bottom portion of a reel hub on which the magnetic tape can be wound, the restricting gear being disposed on the outer peripheral edge of a flange portion projected in the diameter direction of the reel from the outer periphery of the upper end of the reel hub; a cartridge case for storing the reel therein in such a manner that the reel can be rotated, the cartridge case comprising a lower case and an upper case to be superimposed on the upper portion of the lower case, the lower case including in the bottom portion thereof a rotation-driving opening capable of exposing the rotation-driving engaging mechanism; a reel spring interposed between the upper case and reel for energizing the reel toward the lower case side; a reel brake rotatably journaled on the upper case, including a locking gear portion meshingly engageable with the restricting gear of the reel, and energized in the meshingly engaging direction thereof by a brake spring; and, a lid mounted openably and closably in a magnetic tape pull-out opening formed in the cartridge case for pulling out the magnetic tape, the lid being energized in the closing direction thereof by a lid spring,
wherein a plurality of assembling stations, which are respectively arranged in a straight line manner and each of which includes an assembling robot for assembling the respective parts of the magnetic tape cartridge, are respectively capable of delivering sequentially a pallet with the upper case placed thereon, and also wherein reel brake hold mechanism capable of holding the locking gear portion of the reel brake against the energizing force of brake spring in such a manner that the reel brake retreats from the installation area of the reel, lid spring hold mechanism capable of holding the lid engaging portion of the lid spring in such a manner that the lid engaging portion is not in engagement with the lid, and reel hold mechanism capable of holding the reel on the upper case side against the energizing force of the reel spring are driven sequentially by their associated drive mechanism disposed in their associated ones of the assembling stations, whereby the respective parts of the magnetic tape cartridge are assembled onto the upper case by their associated ones of the assembling robots.
Also, in achieving the above object, according to another aspect of the invention, there is provided apparatus for assembling a magnetic tape cartridge, the magnetic tape cartridge comprising: a reel including rotation-driving engaging mechanism for driving or rotating magnetic tape and, a restricting gear for restricting the rotation of the reel, the rotation-driving engaging mechanism being formed on the outer surface of the bottom portion of a reel hub on which the magnetic tape can be wound, the restricting gear being disposed on the outer peripheral edge of a flange portion projected in the diameter direction of the reel from the outer periphery of the upper end of said reel hub; a cartridge case for storing the reel therein in such a manner that the reel can be rotated, the cartridge case comprising a lower case and an upper case to be superimposed on the upper portion of the lower case, the lower case including in the bottom portion thereof a rotation-driving opening capable of exposing the rotation-driving engaging mechanism; a reel spring interposed between the upper case and reel for energizing the reel toward the lower case side; a reel brake rotatable journaled on the upper case, including a locking gear portion meshingly engageable with the restricting gear of the reel, and energized in the meshingly engaging direction thereof by brake spring; and, a lid mounted openably and closably in a magnetic tape pull-out opening formed in the cartridge case for pulling out the magnetic tape, the lid being energized in the closing direction thereof by a lid spring, wherein a plurality of assembling stations, which are respectively arranged in a straight line manner and each of which includes an assembling robot for assembling the respective parts of the magnetic tape cartridge, respectively comprises pallet delivery mechanism capable of delivering sequentially a pallet with the upper case placed thereon, also wherein the pallet comprises reel brake hold mechanism capable of holding the reel brake against the energizing force of the brake spring in such a manner that the reel brake retreats from the installation area of the reel, lid spring hold mechanism capable of holding the lid engaging portion of the lid spring in such a manner that the lid engaging portion is not in engagement with the lid, reel hold mechanism capable of holding the reel on the upper case side against the energizing force of the reel spring, and further wherein the respective hold mechanism are driven sequentially by their associated ones of drive mechanism respectively disposed in their associated ones of the assembling stations.
According to the above-mentioned structure, the reel is assembled to the upper case, which is placed on the pallet to be delivered sequentially to the given assembling positions of the respective assembling stations, while the locking gear portions of the front and rear reel brakes are held by their associated ones of the hold mechanism respectively disposed in the pallet in such a manner that they retreat from the reel installation area; and, at the same time, the lid is also assembled to the upper case, while the lid engaging portion of the lid spring is held by its associated one of the above-mentioned hold mechanism in such a manner that it is not in engagement with the lid. This makes it possible to facilitate the assembling operations of the reel and lid. Since the reel is delivered to the next assembling station while it is held on the upper case side against the energizing force of the reel spring, there is no fear that the reel can be removed from its given position when the pallet is delivered.
Also, the above-mentioned respective hold mechanism are disposed in each of the pallets and, therefore, in the respective assembling stations, there may be disposed only the drive mechanism which are simple in structure and are capable of driving their associated hold mechanism. Thanks to this, the structures of the respective assembling stations can be simplified.
By the way, preferably, each of the hold mechanism may include an arm member journaled in a freely swingable manner, and elastically energizing mechanism capable of clicking the arm member between a hold position and a non-hold position; and, on the swing end side of the arm member to be swung in a direction towards a given position by the energizing force of the drive mechanism which is contacted with the arm member, there may be formed a hold portion for holding the above-mentioned respective parts. In this preferred structure, the drive mechanism is able to click the arm member between the hold position and non-hold position simply by driving a pressure member to advance and retreat, while the pressure member is simple in structure and can be advanced and retreated with respect to the contact portion of the arm member.